The present invention relates generally to radiator cooling fans. More specifically, the invention is directed to a heavy duty radiator cooling fan assembly which may be economically manufactured and facilely assembled while maintaining the stringent performance and endurance standards required in the demanding environment of trucks, off-the-road equipment and other large vehicles.
A variety of fan structures have been developed for use in the cooling systems of automobiles, trucks and other vehicles. These fan structures, or assemblies, must be capable of withstanding extreme environmental conditions while still providing suitable air flow over the radiator and vehicle engine. It is important, therefore, that radiator cooling fans, and particularly those used in trucks and other large vehicles, be ruggedly constructed so as to provide long service life substantially free from maintenance.
In addition, it is important that these fan assemblies weigh as little as possible, since increased weight may adversely affect the operation or useful life of other associated engine components, such as the water pump, clutches and fan pulleys. Accordingly, the construction of prior art cooling fans has required a compromise between strength and durability on the one hand and the overall weight of the fan assembly on the other.
Prior art radiator cooling fans used for trucks and larger vehicles typically comprise an assembly of two hubs between which are mounted a plurality of fan blades. In the past these hubs, which are shaped as spiders, have each had radially extending arms of equal length. In addition, the hubs have been either formed to adjoin one another in their central mounting portion or have been separated by an insert plate. These structural arrangements have resulted in increased weight, difficulty in assembly and installation and generally increased costs of manufacture.